The invention is based on a spray nozzle for window or glass washer systems as generically defined by the preamble to claim 1.
As a rule, known window or glass washer systems for vehicles are used in conjunction with wipers. For headlights, it is sufficient in some cases to use them without wipers, but with a higher pressure. These systems are actuated if the moisture from precipitation is insufficient to clean the vehicle glass. They include a water tank, spray nozzles, and a pump that pumps water, with which cleaning and antifreeze agents are mixed under some circumstances, under pressure out of the water tank via water lines to the spray nozzles. As a rule, the spray nozzles are secured to some part of a vehicle body, such as a hood over the engine compartment, a window frame, or the like.
It is also already known to secure spray nozzles as additional components on the wiper blade and thus to distribute the spraying water over the wiping region directly with a short stream length. Since the spraying water is concentrated on a region in the vicinity of the wiper blade and is wiped off again in the briefest time by the wiping motion, the view is hindered only briefly by the spraying water applied. A disadvantage of such systems is that the effects of weather, especially hail and extreme sunshine, have a major effect on the flexible parts of this arrangement, which are required for spanning the jointed regions between the wiper arm and the wiper blade. The spray nozzles and water lines that are exposed to the relative wind also freeze up quickly at temperatures below the freezing point, unless enough antifreeze is added to the water. As a rule, thawing the frozen water lines and spray nozzles again can be done only with major effort.
Expediently, the spray nozzle has an outward-opening check valve, which prevents the water line from running empty if the washer system goes unused for relatively long periods. These check valves for the most part operate on the order of the spring and ball system. They are intended to prevent the water line from becoming only partly filled, impeding the heat transfer from the heating element to the water. Furthermore, water residues can become locally overheated and can evaporate. This causes calcium deposits that over the course of time plug up the narrow conduits in the spray nozzle.
A spray nozzle with an elastically widenable nozzle part is also known, from Bosch Handelsprogramm 97/98 [Trade Program 97/98], page 29, which opens by the pressure of the washing water and closes if pressure is absent. The spray port is formed by liplike parts of the nozzle part, which in the closed state rest on one another. Although here the entire washing water volume is enclosed as far as the spray port, still it is difficult to achieve a defined geometry and direction of the spray stream.
In an earlier German patent application, DE 198 15 171.3, a wiper arm is described on whose hinge element, or on a wiper rod integrally joined to the hinge element, spray nozzles are disposed. The spray nozzles are located in a nozzle body, which is accommodated in a bulge of the hinge element with a spray opening for the spray stream, or is clipped, protruding downward, in a lateral mount on the wiper rod. It is also possible for two nozzle bodies to be provided, which are joined together by a rigid or flexible connecting piece. The nozzle bodies can be replaced easily and are well protected against environmental factors.
There are also simple versions in which the nozzle bodies are produced integrally and as an injection molded plastic part. The nozzles are either supported fixedly in the nozzle body or are adjustably supported via a ball seat. By means of the nozzle bodies distributed on the wiper arm, the spraying water is well distributed over the wiping region, especially if a spray stream is aimed directly in front of the wiper blade in a lower region. Because as a result of the arrangement the stream lengths are short, the relative wind can have only little effect on the spraying water distribution even at a relatively high vehicle speed.
According to the invention, the spray nozzle has a closure element, which is disposed in the water inlet upstream of a fixed spray opening. By the pressure of the washing water, the elastic admission opening opens, and the washing water is sprayed onto the vehicle window or other glass through the fixed spray port. The fixed spray port guarantees a stable stream geometry, along with a replicable stream direction to suit the adjustment, and optimal impact points. Since the closure element takes up only a little installation space, it can be located in the immediate vicinity of the spray port. It prevents washing water and antifreeze from escaping from the washer system in the pressureless state. Since the closure element is accommodated in the water conduit of the nozzle body and is thus protected, then together with the nozzle body it can even be placed at exposed points, without the risk of becoming damaged.
If one water line supplies a plurality of spray ports, then it is expedient to dispose the closure element upstream of the branch of the water conduits. In one feature of the invention, the closure element, on its leading edge, has an edge with which it is retained between the nozzle body and a separate connection piece for the water line. The connection piece is joined in pressure-tight fashion to the nozzle body, for instance positively by clips or detents or materially by adhesive bonding, welding, and in particular ultrasonic welding. The elastic edge of the closure element can act as a seal in the process. On the trailing edge, the closure element has liplike wall parts, which in the pressureless state rest tightly against one another and close the admission conduit.
An even simpler variant of the invention provides a part of the water line as the closure element; this part is elastic in a region shortly upstream of the connection to the nozzle body and is shaped on the inside such that it closes the water line at this point. A water pressure generated by the pump of the window or glass washer system presses the elastic part of the water line outward at this point and thus uncovers an opening for the spraying water. In a further variant of the invention, a spring element presses from outside against the elastic point of the water line and interrupts the flow through it until a defined pressure is achieved. The spring element can be used either by itself or in addition to a special shaping of the water line.